In the past metallocene catalysts were employed together with an activator or cocatalyst to produce an active olefin polymerization catalyst. For example, W. Kaminsky, et. al., "Polymerization of Olefins With a Homogeneous Zirconium/Alumoxane Catalysts", Adv. Polyolefins [Proc. ACS Int. Symp.] Meeting Date 1985, 361-371. Edited by Seymour, et. al., Plenum: New York, N.Y.; published 1987 disclosed that cyclopentadienyl complexes of the general formula Cp.sub.2 MR.sub.2 are by themselves active polymerization catalysts, where Cp is a cyclopentadienyl radical that is substituted or unsubstituted, M is Ti, Zr or Hf and R is an alkyl. When these homogeneous catalysts are contacted with an alkyl aluminum or alumoxane these catalysts are particularly active.
K. Soga, et. al., "Activation of SiO.sub.2 -Supported Zirconocene Catalysts by common trialkylaluminums", 194 Makromol. Chem. 3499-3504 (1993), described the deposition of a Cp.sub.2 ZrCl.sub.2 metallocene on SiO.sub.2 which has been reacted with a Cl.sub.2 Si(CH.sub.3).sub.2 compound. This catalyst system is then introduced into an olefin polymerization process in the presence of an aluminum alkyl.
U.S. Pat. Nos. 5,162,466 and 5,214,173 discuss neutral cyclopentadienyl dicarbollide unsupported complexes of Ti, Zr and Hf as active polymerization catalysts in the absence of a cocatalyst. However, these complexes are very difficult and expensive to synthesize.
It would be highly desirable to have an active polymerization supported catalyst that can polymerize olefins without requiring an activator. A need exists in the industry for a simple catalyst system that does not require an activator to polymerize olefins.